/**
 * Copyright 2019 吉鼎科技.

 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.easyplatform.org.objectweb.asm;

/**
 * A visitor to visit a Java method. The methods of this interface must be
 * called in the following order: [ <tt>visitAnnotationDefault</tt> ] (
 * <tt>visitAnnotation</tt> | <tt>visitParameterAnnotation</tt> |
 * <tt>visitAttribute</tt> )* [ <tt>visitCode</tt> ( <tt>visitFrame</tt> |
 * <tt>visit</tt><i>X</i>Insn</tt> | <tt>visitLabel</tt> |
 * <tt>visitTryCatchBlock</tt> | <tt>visitLocalVariable</tt> |
 * <tt>visitLineNumber</tt>)* <tt>visitMaxs</tt> ] <tt>visitEnd</tt>. In
 * addition, the <tt>visit</tt><i>X</i>Insn</tt> and <tt>visitLabel</tt> methods
 * must be called in the sequential order of the bytecode instructions of the
 * visited code, <tt>visitTryCatchBlock</tt> must be called <i>before</i> the
 * labels passed as arguments have been visited, and the
 * <tt>visitLocalVariable</tt> and <tt>visitLineNumber</tt> methods must be
 * called <i>after</i> the labels passed as arguments have been visited.
 * 
 * @author Eric Bruneton
 */
public interface MethodVisitor {

	// //
	// -------------------------------------------------------------------------
	// // Annotations and non standard attributes
	// //
	// -------------------------------------------------------------------------
	//
	// /**
	// * Visits the default value of this annotation interface method.
	// *
	// * @return a visitor to the visit the actual default value of this
	// * annotation interface method, or <tt>null</tt> if this visitor
	// * is not interested in visiting this default value. The 'name'
	// * parameters passed to the methods of this annotation visitor are
	// * ignored. Moreover, exacly one visit method must be called on this
	// * annotation visitor, followed by visitEnd.
	// */
	// AnnotationVisitor visitAnnotationDefault();
	//
	// /**
	// * Visits an annotation of this method.
	// *
	// * @param desc the class descriptor of the annotation class.
	// * @param visible <tt>true</tt> if the annotation is visible at runtime.
	// * @return a visitor to visit the annotation values, or <tt>null</tt> if
	// * this visitor is not interested in visiting this annotation.
	// */
	// AnnotationVisitor visitAnnotation(String desc, boolean visible);
	//
	// /**
	// * Visits an annotation of a parameter this method.
	// *
	// * @param parameter the parameter index.
	// * @param desc the class descriptor of the annotation class.
	// * @param visible <tt>true</tt> if the annotation is visible at runtime.
	// * @return a visitor to visit the annotation values, or <tt>null</tt> if
	// * this visitor is not interested in visiting this annotation.
	// */
	// AnnotationVisitor visitParameterAnnotation(
	// int parameter,
	// String desc,
	// boolean visible);

	/**
	 * Visits a non standard attribute of this method.
	 * 
	 * @param attr
	 *            an attribute.
	 */
	void visitAttribute(Attribute attr);

	/**
	 * Starts the visit of the method's code, if any (i.e. non abstract method).
	 */
	void visitCode();

	/**
	 * Visits the current state of the local variables and operand stack
	 * elements. This method must(*) be called <i>just before</i> any
	 * instruction <b>i</b> that follows an unconditional branch instruction
	 * such as GOTO or THROW, that is the target of a jump instruction, or that
	 * starts an exception handler block. The visited types must describe the
	 * values of the local variables and of the operand stack elements <i>just
	 * before</i> <b>i</b> is executed. <br>
	 * <br>
	 * (*) this is mandatory only for classes whose version is greater than or
	 * equal to {@link Opcodes#V1_6 V1_6}. <br>
	 * <br>
	 * Packed frames are basically "deltas" from the state of the previous frame
	 * (very first frame is implicitly defined by the method's parameters and
	 * access flags):
	 * <ul>
	 * <li>{@link Opcodes#F_SAME} representing frame with exactly the same
	 * locals as the previous frame and with the empty stack.</li>
	 * <li>{@link Opcodes#F_SAME1} representing frame with exactly the same
	 * locals as the previous frame and with single value on the stack (
	 * <code>nStack</code> is 1 and <code>stack[0]</code> contains value for the
	 * type of the stack item).</li>
	 * <li>{@link Opcodes#F_APPEND} representing frame with current locals are
	 * the same as the locals in the previous frame, except that additional
	 * locals are defined (<code>nLocal</code> is 1, 2 or 3 and
	 * <code>local</code> elements contains values representing added types).</li>
	 * <li>{@link Opcodes#F_CHOP} representing frame with current locals are the
	 * same as the locals in the previous frame, except that the last 1-3 locals
	 * are absent and with the empty stack (<code>nLocals</code> is 1, 2 or 3).</li>
	 * <li>{@link Opcodes#F_FULL} representing complete frame data.</li> </li>
	 * </ul>
	 * 
	 * @param type
	 *            the type of this stack map frame. Must be
	 *            {@link Opcodes#F_NEW} for expanded frames, or
	 *            {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND},
	 *            {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or
	 *            {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for
	 *            compressed frames.
	 * @param nLocal
	 *            the number of local variables in the visited frame.
	 * @param local
	 *            the local variable types in this frame. This array must not be
	 *            modified. Primitive types are represented by
	 *            {@link Opcodes#TOP}, {@link Opcodes#INTEGER},
	 *            {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
	 *            {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
	 *            {@link Opcodes#UNINITIALIZED_THIS} (long and double are
	 *            represented by a single element). Reference types are
	 *            represented by String objects (representing internal names),
	 *            and uninitialized types by Label objects (this label
	 *            designates the NEW instruction that created this uninitialized
	 *            value).
	 * @param nStack
	 *            the number of operand stack elements in the visited frame.
	 * @param stack
	 *            the operand stack types in this frame. This array must not be
	 *            modified. Its content has the same format as the "local"
	 *            array.
	 * @throws IllegalStateException
	 *             if a frame is visited just after another one, without any
	 *             instruction between the two (unless this frame is a
	 *             Opcodes#F_SAME frame, in which case it is silently ignored).
	 */
	void visitFrame(int type, int nLocal, Object[] local, int nStack,
			Object[] stack);

	// -------------------------------------------------------------------------
	// Normal instructions
	// -------------------------------------------------------------------------

	/**
	 * Visits a zero operand instruction.
	 * 
	 * @param opcode
	 *            the opcode of the instruction to be visited. This opcode is
	 *            either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1,
	 *            ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1,
	 *            FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD,
	 *            LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD,
	 *            IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE,
	 *            SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1,
	 *            DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB,
	 *            IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM,
	 *            FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR,
	 *            IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D,
	 *            L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S,
	 *            LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN,
	 *            DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER,
	 *            or MONITOREXIT.
	 */
	void visitInsn(int opcode);

	/**
	 * Visits an instruction with a single int operand.
	 * 
	 * @param opcode
	 *            the opcode of the instruction to be visited. This opcode is
	 *            either BIPUSH, SIPUSH or NEWARRAY.
	 * @param operand
	 *            the operand of the instruction to be visited.<br>
	 *            When opcode is BIPUSH, operand value should be between
	 *            Byte.MIN_VALUE and Byte.MAX_VALUE.<br>
	 *            When opcode is SIPUSH, operand value should be between
	 *            Short.MIN_VALUE and Short.MAX_VALUE.<br>
	 *            When opcode is NEWARRAY, operand value should be one of
	 *            {@link Opcodes#T_BOOLEAN}, {@link Opcodes#T_CHAR},
	 *            {@link Opcodes#T_FLOAT}, {@link Opcodes#T_DOUBLE},
	 *            {@link Opcodes#T_BYTE}, {@link Opcodes#T_SHORT},
	 *            {@link Opcodes#T_INT} or {@link Opcodes#T_LONG}.
	 */
	void visitIntInsn(int opcode, int operand);

	/**
	 * Visits a local variable instruction. A local variable instruction is an
	 * instruction that loads or stores the value of a local variable.
	 * 
	 * @param opcode
	 *            the opcode of the local variable instruction to be visited.
	 *            This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD,
	 *            ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
	 * @param var
	 *            the operand of the instruction to be visited. This operand is
	 *            the index of a local variable.
	 */
	void visitVarInsn(int opcode, int var);

	/**
	 * Visits a type instruction. A type instruction is an instruction that
	 * takes the internal name of a class as parameter.
	 * 
	 * @param opcode
	 *            the opcode of the type instruction to be visited. This opcode
	 *            is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
	 * @param type
	 *            the operand of the instruction to be visited. This operand
	 *            must be the internal name of an object or array class (see
	 *            {@link Type#getInternalName() getInternalName}).
	 */
	void visitTypeInsn(int opcode, String type);

	/**
	 * Visits a field instruction. A field instruction is an instruction that
	 * loads or stores the value of a field of an object.
	 * 
	 * @param opcode
	 *            the opcode of the type instruction to be visited. This opcode
	 *            is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
	 * @param owner
	 *            the internal name of the field's owner class (see
	 *            {@link Type#getInternalName() getInternalName}).
	 * @param name
	 *            the field's name.
	 * @param desc
	 *            the field's descriptor (see {@link Type Type}).
	 */
	void visitFieldInsn(int opcode, String owner, String name, String desc);

	/**
	 * Visits a method instruction. A method instruction is an instruction that
	 * invokes a method.
	 * 
	 * @param opcode
	 *            the opcode of the type instruction to be visited. This opcode
	 *            is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC,
	 *            INVOKEINTERFACE or INVOKEDYNAMIC.
	 * @param owner
	 *            the internal name of the method's owner class (see
	 *            {@link Type#getInternalName() getInternalName}) or
	 *            {@link cn.easyplatform.org.objectweb.asm.Opcodes#INVOKEDYNAMIC_OWNER}
	 *            .
	 * @param name
	 *            the method's name.
	 * @param desc
	 *            the method's descriptor (see {@link Type Type}).
	 */
	void visitMethodInsn(int opcode, String owner, String name, String desc);

	/**
	 * Visits a jump instruction. A jump instruction is an instruction that may
	 * jump to another instruction.
	 * 
	 * @param opcode
	 *            the opcode of the type instruction to be visited. This opcode
	 *            is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ,
	 *            IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,
	 *            IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
	 * @param label
	 *            the operand of the instruction to be visited. This operand is
	 *            a label that designates the instruction to which the jump
	 *            instruction may jump.
	 */
	void visitJumpInsn(int opcode, Label label);

	/**
	 * Visits a label. A label designates the instruction that will be visited
	 * just after it.
	 * 
	 * @param label
	 *            a {@link Label Label} object.
	 */
	void visitLabel(Label label);

	// -------------------------------------------------------------------------
	// Special instructions
	// -------------------------------------------------------------------------

	/**
	 * Visits a LDC instruction.
	 * 
	 * @param cst
	 *            the constant to be loaded on the stack. This parameter must be
	 *            a non null {@link Integer}, a {@link Float}, a {@link Long}, a
	 *            {@link Double} a {@link String} (or a {@link Type} for
	 *            <tt>.class</tt> constants, for classes whose version is 49.0
	 *            or more).
	 */
	void visitLdcInsn(Object cst);

	/**
	 * Visits an IINC instruction.
	 * 
	 * @param var
	 *            index of the local variable to be incremented.
	 * @param increment
	 *            amount to increment the local variable by.
	 */
	void visitIincInsn(int var, int increment);

	/**
	 * Visits a TABLESWITCH instruction.
	 * 
	 * @param min
	 *            the minimum key value.
	 * @param max
	 *            the maximum key value.
	 * @param dflt
	 *            beginning of the default handler block.
	 * @param labels
	 *            beginnings of the handler blocks. <tt>labels[i]</tt> is the
	 *            beginning of the handler block for the <tt>min + i</tt> key.
	 */
	void visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels);

	/**
	 * Visits a LOOKUPSWITCH instruction.
	 * 
	 * @param dflt
	 *            beginning of the default handler block.
	 * @param keys
	 *            the values of the keys.
	 * @param labels
	 *            beginnings of the handler blocks. <tt>labels[i]</tt> is the
	 *            beginning of the handler block for the <tt>keys[i]</tt> key.
	 */
	void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels);

	/**
	 * Visits a MULTIANEWARRAY instruction.
	 * 
	 * @param desc
	 *            an array type descriptor (see {@link Type Type}).
	 * @param dims
	 *            number of dimensions of the array to allocate.
	 */
	void visitMultiANewArrayInsn(String desc, int dims);

	// -------------------------------------------------------------------------
	// Exceptions table entries, debug information, max stack and max locals
	// -------------------------------------------------------------------------

	/**
	 * Visits a try catch block.
	 * 
	 * @param start
	 *            beginning of the exception handler's scope (inclusive).
	 * @param end
	 *            end of the exception handler's scope (exclusive).
	 * @param handler
	 *            beginning of the exception handler's code.
	 * @param type
	 *            internal name of the type of exceptions handled by the
	 *            handler, or <tt>null</tt> to catch any exceptions (for
	 *            "finally" blocks).
	 * @throws IllegalArgumentException
	 *             if one of the labels has already been visited by this visitor
	 *             (by the {@link #visitLabel visitLabel} method).
	 */
	void visitTryCatchBlock(Label start, Label end, Label handler, String type);

	/**
	 * Visits a local variable declaration.
	 * 
	 * @param name
	 *            the name of a local variable.
	 * @param desc
	 *            the type descriptor of this local variable.
	 * @param signature
	 *            the type signature of this local variable. May be
	 *            <tt>null</tt> if the local variable type does not use generic
	 *            types.
	 * @param start
	 *            the first instruction corresponding to the scope of this local
	 *            variable (inclusive).
	 * @param end
	 *            the last instruction corresponding to the scope of this local
	 *            variable (exclusive).
	 * @param index
	 *            the local variable's index.
	 * @throws IllegalArgumentException
	 *             if one of the labels has not already been visited by this
	 *             visitor (by the {@link #visitLabel visitLabel} method).
	 */
	void visitLocalVariable(String name, String desc, String signature,
			Label start, Label end, int index);

	/**
	 * Visits a line number declaration.
	 * 
	 * @param line
	 *            a line number. This number refers to the source file from
	 *            which the class was compiled.
	 * @param start
	 *            the first instruction corresponding to this line number.
	 * @throws IllegalArgumentException
	 *             if <tt>start</tt> has not already been visited by this
	 *             visitor (by the {@link #visitLabel visitLabel} method).
	 */
	void visitLineNumber(int line, Label start);

	/**
	 * Visits the maximum stack size and the maximum number of local variables
	 * of the method.
	 * 
	 * @param maxStack
	 *            maximum stack size of the method.
	 * @param maxLocals
	 *            maximum number of local variables for the method.
	 */
	void visitMaxs(int maxStack, int maxLocals);

	/**
	 * Visits the end of the method. This method, which is the last one to be
	 * called, is used to inform the visitor that all the annotations and
	 * attributes of the method have been visited.
	 */
	void visitEnd();
}
